Widespread use of incarceration in the US, coupled with high rates of inmate fatherhood, has raised concerns for the wellbeing of more than two million affected children. The deleterious and long term effects of incarceration on men's financial and relationship stability are well-established. Incarceration also compromises family material wellbeing, and partners are at risk of hardship and stress, which may diminish capacity for positive parenting and harm children's development. However, little is known about the links between father incarceration and family material wellbeing. Using the Fragile Families and Child Wellbeing survey we examine the extent to which fathers' incarceration increases the material hardship experienced by their families. We find that incarceration indeed increases hardship for families, by both reducing household income and disrupting family relationships and routines. These findings underscore the need for criminal justice agencies and social service providers to help mitigate the risks associated with a father's incarceration.